CN220754095U - Transformer neutral point grounding resistor cabinet - Google Patents
Transformer neutral point grounding resistor cabinet Download PDFInfo
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- CN220754095U CN220754095U CN202322210482.0U CN202322210482U CN220754095U CN 220754095 U CN220754095 U CN 220754095U CN 202322210482 U CN202322210482 U CN 202322210482U CN 220754095 U CN220754095 U CN 220754095U
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- isolating switch
- transformer
- neutral point
- resistor
- grounding
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- 230000007935 neutral effect Effects 0.000 title claims abstract description 43
- 238000004804 winding Methods 0.000 claims abstract description 9
- 238000012423 maintenance Methods 0.000 abstract description 9
- 238000007689 inspection Methods 0.000 abstract description 5
- 239000004020 conductor Substances 0.000 description 9
- 239000012212 insulator Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000003822 epoxy resin Substances 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 229920000647 polyepoxide Polymers 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000010125 resin casting Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
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Abstract
The neutral point grounding resistance cabinet of the transformer comprises a cabinet body, wherein a current transformer connected with a neutral point of a star-shaped winding at the low voltage side of the power transformer is arranged in the cabinet body, and a busbar is arranged above the cabinet body; the current output end of the current transformer is connected with the first isolating switch incoming contact; the busbar is respectively connected with the outgoing line contacts of the first isolating switch, the second isolating switch and the third isolating switch, the incoming line contact of the second isolating switch is connected with the grounding terminal, the incoming line contact of the third isolating switch is connected with the head end of the resistor, and the tail end of the resistor is connected with the grounding terminal; the neutral point operation mode can be flexibly changed through the isolating switches arranged on the power grid side, the grounding side and the resistor side, so that not only is the further protection capability provided for the inspection maintenance and operation and maintenance personnel safety of equipment, but also the system scheduling requirement is met, and the reliable and stable operation of the power system can be ensured; the utility model has the characteristics of low engineering cost, reliable operation of the power grid system and convenient and safe manual maintenance.
Description
Technical Field
The utility model belongs to the technical field of power engineering neutral point grounding, and particularly relates to a transformer neutral point grounding resistor cabinet.
Background
The low-voltage side neutral point of the power transformer usually adopts a wiring mode of grounding through a resistor, a fault line is judged through zero sequence protection of each line, and when a single-phase grounding fault occurs in a certain line, the zero sequence protection action of the line breaks the circuit breaker of the line, so that a fault loop is quickly cut off, and the expansion of accidents is avoided.
According to the operation requirement of the power system, the neutral point grounding mode of the power transformer can be an ungrounded system, a direct grounding system, a resistor grounding system and an arc suppression coil grounding system, and through flexibly adjusting the neutral point grounding mode, the overvoltage level and the insulation level of the power system are ensured, and the power supply reliability of the system and the safety of electrical equipment are ensured. The low-voltage side of the power transformer is usually in a triangular wiring or star-shaped wiring mode, a Z-shaped winding grounding transformer is needed to be adopted under the triangular wiring mode of the power transformer, and the neutral point of the grounding transformer is connected with the resistor; in the star connection of the power transformer, the neutral point of the power transformer is connected to a resistor. When the neutral point grounding resistor cabinet of the power transformer works, the internal current has great potential safety hazard to a human body, so that the neutral point grounding resistor of the power transformer is required to be disconnected from a power grid during maintenance and inspection, and operators can cause personal injury and even death when the isolating switch is carelessly electrified to operate and the resistor cabinet is opened.
The Chinese patent publication No. CN 206542106U discloses a transformer neutral point grounding resistance cabinet, comprising: the transformer three-phase winding, the resistor and the current transformer, one end of the resistor is connected with the neutral point of the transformer three-phase winding and the other end of the resistor is connected with the current transformer, and the current transformer is directly grounded, but in the patent, the resistor is directly connected with the neutral point of the transformer, no obvious disconnection point exists, and the potential safety hazard exists for operators, and according to the wiring form, the low-voltage side of the transformer can only be in a resistor grounding operation mode, and the operation mode is single.
The Chinese patent with the bulletin number of CN208062789U discloses a transformer neutral point grounding resistor cabinet complete set device, which comprises a first isolating switch, a grounding transformer, a second isolating switch, a grounding resistor, a current transformer, an intelligent controller and a cabinet; the grounding transformer inlet wire end is connected with the power supply bus through the first isolating switch, the neutral point of the grounding transformer is connected with the first end of the grounding resistor through the second isolating switch, the second end of the grounding resistor is connected with the first end of the current transformer, and the second end of the current transformer is connected to the ground.
Disclosure of Invention
In order to overcome the defects in the prior art, the utility model aims to provide a transformer neutral point grounding resistor cabinet, which is connected with a neutral point of a low-voltage side star-shaped winding of a power transformer, so that the overvoltage of a power grid can be reduced, and the safety and the reliability of a power grid system adopting the neutral point to be grounded through resistors are improved; the neutral point operation mode can be flexibly changed by arranging the isolating switches on the power grid side, the grounding side and the resistor side, so that the device not only provides further protection capability for the inspection maintenance and operation maintenance personnel safety of the device, but also meets the system scheduling requirement, and can ensure the reliable and stable operation of the power system.
In order to achieve the above object, the technical scheme of the present utility model is as follows:
the neutral point grounding resistance cabinet of the transformer comprises a cabinet body 10, wherein a current transformer 4 connected with a neutral point of a star-shaped winding on a low-voltage side of a power transformer 8 is arranged in the cabinet body 10, and a busbar 5 is arranged above the inside of the cabinet body 10; the current output end of the current transformer 4 is connected with the incoming line contact of the first isolating switch 1; the busbar 5 is respectively connected with outgoing line contacts of the first isolating switch 1, the second isolating switch 2 and the third isolating switch 3, incoming line contacts of the second isolating switch 2 are connected with the grounding terminal 9, incoming line contacts of the third isolating switch 3 are connected with the head end S1 of the resistor 6, and the tail end S2 of the resistor 6 is connected with the grounding terminal 9.
The first isolating switch 1, the second isolating switch 2 and the third isolating switch 3 are all single-phase isolating switches.
The low-voltage side of the power transformer 8 is a star-shaped wiring transformer of Yyn0 or YYyn 0d 11.
The working voltage of the low-voltage side of the power transformer 8 is 6-35kV.
Compared with the prior art, the utility model has the beneficial effects that:
1. compared with the prior art, when a power transformer with a star-shaped wiring on the low-voltage side has single-phase grounding of a certain loop on the low-voltage side, the utility model can reduce the short-circuit current during single-phase grounding fault, ensure the reliable action of grounding protection and provide the reliability of power supply of the system.
2. The utility model is provided with the isolating switches on the power grid side, the grounding side and the resistor side, on one hand, double isolation protection is provided for the busbar end and the resistor end, the installation, the use, the inspection and the maintenance of equipment are convenient, and more importantly, the safety of operators is greatly improved; on the other hand, the neutral point operation mode can be flexibly changed according to the requirements of the power system, the system scheduling requirements are met, and the reliable and stable operation of the power system is ensured.
3. The neutral point grounding resistor cabinet of the transformer does not contain a grounding transformer, and when the power transformer is of a star-shaped wiring structure with a neutral line, the resistor can be matched with the star-shaped wiring structure for use.
In summary, compared with the prior art, the utility model reduces the overvoltage of the power grid and improves the safety and reliability of the power grid system adopting the neutral point to be grounded through the resistor by connecting the resistor cabinet with the neutral point of the star-shaped winding at the low voltage side of the power transformer; the neutral point operation mode is flexibly changed by arranging the isolating switches on the power grid side, the grounding side and the resistor side, so that the device not only provides further protection capability for the inspection maintenance and operation maintenance personnel safety of the device, but also meets the system scheduling requirement, and ensures the reliable and stable operation of the power system.
Drawings
Fig. 1 is a schematic structural diagram of a transformer neutral point grounding resistor cabinet according to the present utility model.
Fig. 2 is a schematic diagram of the front view structure of the transformer neutral point grounding resistor cabinet.
Fig. 3 is a schematic diagram of a left-hand structure of a cabinet body of the transformer neutral point grounding resistance cabinet.
Fig. 4 is a schematic diagram of a right-side view of a cabinet body of the transformer neutral point grounding resistance cabinet.
In the figure: the three-phase current transformer comprises a first isolating switch 1, a second isolating switch 2, a third isolating switch 3, a current transformer 4, a busbar 5, a resistor 6, a power cable 7, a power transformer 8, a grounding terminal 9, a cabinet 10, a post insulator 11 and a connecting conductor 12.
Detailed Description
The structural and operational principles of the present utility model will be described in detail with reference to the accompanying drawings.
The utility model has the following structural principle: as shown in fig. 1, the neutral point grounding resistor cabinet of the transformer comprises a cabinet body 10, wherein a current transformer 4 is arranged in the cabinet body 10, and a busbar 5 is arranged above the inside of the cabinet body 10; the current input end P1 of the current transformer 4 is connected with the neutral point of the star-shaped winding at the low voltage side of the power transformer 8 through the power cable 7, and the current output end P2 of the current transformer 4 is connected with the incoming contact of the first isolating switch 1 through the connecting conductor 12; the busbar 5 is respectively connected with outgoing line contacts of the first isolating switch 1, the second isolating switch 2 and the third isolating switch 3, incoming line contacts of the second isolating switch 2 are connected with the grounding terminal 9 through a connecting conductor 12, incoming line contacts of the third isolating switch 3 are connected with the head end S1 of the resistor 6 through the connecting conductor 12, and the tail end S2 of the resistor 6 is connected with the grounding terminal 9 through the connecting conductor 12.
As shown in fig. 2-4, the first isolating switch 1 and the third isolating switch 3 are installed at two side positions of the inner top of the cabinet body 10, the second isolating switch 2 is installed at the middle position of the inner top of the cabinet body 10, the current transformer 4 is installed at the bottom of the cabinet body 10 and is positioned below the first isolating switch 1, and the lower incoming line of the power cable 7 is realized; the resistor 6 is arranged at the bottom of the cabinet 10 and below the third isolating switch 3 through a post insulator 11; the busbar 5 is fixed above the inside of the cabinet 10 through a post insulator 11, the ground terminal 9 near the tail end S2 of the resistor 6 is arranged at the bottom of the cabinet 10, and the connecting conductor 12 connecting the first isolating switch 1 and the current transformer 4 is fixed on the side wall of the cabinet 10 through the post insulator 11.
The first isolating switch 1, the second isolating switch 2 and the third isolating switch 3 are single-phase isolating switches, and the model is GN19.
The current transformer 4 is an epoxy resin casting fully-closed support column, the model is LZZB, the zero sequence current of the measuring system is measured, and the current transformation ratio can be 1A or 5A.
The resistor 6 is formed by serially connecting multiple layers of resistors, has a burnt wire or grid structure, is of an NGR type, is made of a high heat-resistant alloy material, and has the advantages of high conductivity, strong through-flow capability, high temperature resistance, stable resistance, corrosion resistance, flame resistance, explosion resistance and high reliability; the resistance value is from 1 to 2000 omega, the short-time through current can be 1 to 2000A, and the short-time through current time can be 10s, 15s, 30s, 60s and 2h.
The low-voltage side of the power transformer 8 is a star-shaped wiring transformer with Yyn0 or YYyn 0d11, the working voltage of the low-voltage side of the power transformer 8 can be 6-35kV, and other reasonable values can be adopted according to actual conditions, so that the working voltage is not particularly limited.
One end of the grounding terminal 9 is connected with the incoming contact of the second isolating switch 2 and the tail end S2 of the resistor 6, and the other end of the grounding terminal is connected with a substation grounding main network to realize grounding equipotential.
The cabinet body 10 is made of stainless steel, the thickness of a steel plate is not less than 2.0mm, the corrosion resistance is strong, and the protection grade is IP54.
The pillar insulator 11 is made of epoxy resin, has good insulativity, strong anti-interference and corrosion resistance, and is of the type ZJ-XQ, wherein X is of the voltage class of 6, 10 or 35.
The busbar 5, the grounding terminal 9 and the connecting conductor 12 are rectangular copper conductors.
The power cable 7 is a single-core copper conductor cable, and the model is YJV22 or YJY23.
The working principle of the utility model is as follows:
according to the transformer neutral point grounding resistance cabinet provided by the utility model, the obvious disconnection point between the system side and the power grid side is realized through the first isolating switch 1, the flexible operation mode of direct grounding of the low-voltage side of the transformer is realized through the second isolating switch 2, and the obvious disconnection point between the resistor and the system is realized through the third isolating switch 3; after the isolating switch is opened, a reliable insulation gap is established, and equipment or a line to be overhauled is separated from a power supply by an obvious disconnection point, so that the safety of overhauling personnel and equipment is ensured.
The specific mode is as follows:
equipment overhaul mode: the first isolating switch 1 is switched off, the second isolating switch 2 is switched on, the third isolating switch 3 is switched off, and the first isolating switch 1 and the third isolating switch 3 realize dual isolation protection of a power grid side and a resistor side.
The system is not operating at ground: the first isolating switch 1 is switched off or the second isolating switch 2 is switched off and the third isolating switch 3 is switched off simultaneously.
The system operates via resistive ground: the first isolating switch 1 is switched on, the second isolating switch 2 is switched off, the third isolating switch 3 is switched on, and the current transformer 4 measures the grounding current through the resistor.
The system is directly operated in ground: the first isolating switch 1 is switched on, the second isolating switch 2 is switched on, the third isolating switch 3 is switched off, and the current transformer 4 measures direct grounding current.
The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the utility model.
Claims (4)
1. The utility model provides a transformer neutral point ground resistance cabinet, includes the cabinet body (10), its characterized in that: a current transformer (4) connected with a neutral point of a star-shaped winding at the low voltage side of the power transformer (8) is arranged in the cabinet body (10), and a busbar (5) is arranged above the cabinet body (10); the current output end of the current transformer (4) is connected with the incoming contact of the first isolating switch (1); the busbar (5) is respectively connected with outgoing line contacts of the first isolating switch (1), the second isolating switch (2) and the third isolating switch (3), the incoming line contact of the second isolating switch (2) is connected with the grounding terminal (9), the incoming line contact of the third isolating switch (3) is connected with the head end (S1) of the resistor (6), and the tail end (S2) of the resistor (6) is connected with the grounding terminal (9).
2. A transformer neutral point grounded resistance cabinet according to claim 1, wherein: the first isolating switch (1), the second isolating switch (2) and the third isolating switch (3) are all single-phase isolating switches.
3. A transformer neutral point grounded resistance cabinet according to claim 1, wherein: and the low-voltage side of the power transformer (8) is a star-shaped wiring transformer with Yyn0 or YYyn 0d 11.
4. A transformer neutral point grounded resistance cabinet according to claim 1, wherein: the working voltage of the low-voltage side of the power transformer (8) is 6-35kV.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322210482.0U CN220754095U (en) | 2023-08-17 | 2023-08-17 | Transformer neutral point grounding resistor cabinet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322210482.0U CN220754095U (en) | 2023-08-17 | 2023-08-17 | Transformer neutral point grounding resistor cabinet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220754095U true CN220754095U (en) | 2024-04-09 |
Family
ID=90548942
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202322210482.0U Active CN220754095U (en) | 2023-08-17 | 2023-08-17 | Transformer neutral point grounding resistor cabinet |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220754095U (en) |
-
2023
- 2023-08-17 CN CN202322210482.0U patent/CN220754095U/en active Active
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